Biological sciences

Mineralization of cartilage is a key step in the development and growth of bone. A mineralization experiment conducted with rates reveals that the enzyme m-Calpain, a Ca2+ -dependent neutral cysteine proteinase, controls the mineralization of cartilages by degrading proteoglycan during development of the cells. The amount of m-Calpain and its activity in pelleted cultures of rat growth plate chondrocytes increases as the chondrocytes differentiate into the hypertrophic cells and mineralization takes place. In the presence of m-Calpain inhibitors matrix mineralization is suppressed.

Progression and recapitulation of the chondrocyte differentiation program: cartilage matrix protein is a marker for cartilage maturation

Article Abstract:

A study was conducted to examine the morphogenetic role of cartilage matrix protein (CMP) during endochondral bone formation. Altering the expression of CMP resulted in changes in the progression of proliferation, maturation and hypertrophy of chondrocytes in the cartilaginous anlage of bones. A model explaining the relationship between chondrocytes and their extracellular environment and the regulation of differentiation of chondrocytes in the proliferative and hypertrophic stage is presented.

Characterization of the mineralization process in cultures of rabbit growth plate chrondocytes

Article Abstract:

A comparative study of growth plate chondocytes in vivo and in cultured collagen-coated dishes showed that the latter is an appropriate model for the study of cartilage mineralization. Using electron microscopy and Fourier transform infrared spectroscopy, it was shown that small apatite crystals found in the ribs of live rabbits were also present in the cultured chondrocytes. The spectral feautures of these crystals were also studied and were found to be similar to those formed in vivo.